2019, Velkos, Georgios, Krylov, Denis S., Kirkpatrick, Kyle, Spree, Lukas, Dubrovin, Vasilii, Büchner, Bernd, Avdoshenko, Stanislav M., Bezmelnitsyn, Valeriy, Davis, Sean, Faust, Paul, Duchamp, James, Dorn, Harry C., Popov, Alexey A.

The azafullerene Tb 2 @C 79 N is found to be a single-molecule magnet with a high 100-s blocking temperature of magnetization of 24 K and large coercivity. Tb magnetic moments with an easy-axis single-ion magnetic anisotropy are strongly coupled by the unpaired spin of the single-electron Tb−Tb bond. Relaxation of magnetization in Tb 2 @C 79 N below 15 K proceeds via quantum tunneling of magnetization with the characteristic time τ QTM =16 462±1230 s. At higher temperature, relaxation follows the Orbach mechanism with a barrier of 757±4 K, corresponding to the excited states, in which one of the Tb spins is flipped. © 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.